During the International Electron Device Meeting (IEDM) exhibition we got some updates about STT-MRAM research done at IBM, Samsung and Hynix-Grandis (who are researching STT-MRAM together).

IBM is working together with TDK and has presented a new 4-kbit perpendicular STT-MRAM array using tunnel junctions. Samsung has presented an on-axis MRAM with a novel MTJ, which they say open he way towards sub-30nm scaling. Using ferromagnetic electrode and a different MTJ structure design, Samsung think that they can scale this to a sub-20nm level.

Digitimes reports that Macronix has signed an agreement with IBM to continue to co-develop phase-change memory (PCM) technology. The company said it is optimistic about the outlook for PCM, which is likely to be a successor to all memory products used in computers and consumer electronics devices.

IBM is providing a preview of its new STT-MRAM technology. They have produced a 4-Kbit test device, using a magnetic tunnel junction (MTJ) with MgO tunnel barriers. They say that the new technology could enable a 64-Mbit MRAM (90nm). STT-RAM also uses less power than toggle MRAM. The STT-RAM is part of the joint-research with TDK, announced in 2007.

In two papers published in the April 11 issue of Science, IBM Fellow Stuart Parkin and colleagues at the IBM Almaden Research Center in San Jose describe both the fundamentals of a technology dubbed "racetrack" memory as well as a milestone in that technology. This milestone could lead to electronic devices capable of storing far more data in the same amount of space than is possible today, with lightning-fast boot times, far lower cost and unprecedented stability and durability.

Within the next ten years, racetrack memory, so named because the data "races" around the wire "track," could lead to solid state electronic devices - with no moving parts, and therefore more durable - capable of holding far more data in the same amount of space than is possible today. For example, this technology could enable a handheld device such as an mp3 player to store around 500,000 songs or around 3,500 movies - 100 times more than is possible today - with far lower cost and power consumption. The devices would not only store vastly more information in the same space, but also require much less power and generate much less heat, and be practically unbreakable; the result: massive amounts of personal storage that could run on a single battery for weeks at a time and last for decades.

For nearly fifty years, scientists have explored the possibility of storing information in magnetic domain walls, which are the boundaries between magnetic regions or "domains" in magnetic materials. Until now, manipulating domain walls was expensive, complex, and used significant power to generate the fields necessary to do so. In the paper describing their milestone, "Current Controlled Magnetic Domain-Wall Nanowire Shift Register," Dr. Parkin and his team describe how this long-standing obstacle can be overcome by taking advantage of the interaction of spin polarized current with magnetization in the domain walls; this results in a spin transfer torque on the domain wall, causing it to move. The use of spin momentum transfer considerably simplifies the memory device since the current is passed directly across the domain wall without the need for any additional field generators.

Read more here (Nanotechnology now) 

After partnering with IBM in August, TDK now plans to produce high-capacity MRAM chips in 2008. It plans to make even higher-density chips in 2011.

IBM has linked with Japan's TDK to develop so-called spin torque transfer RAM (random access memory) or STT-RAM. In STT-RAM, an electric current is applied to a magnet to change the direction of the magnetic field. The direction of the magnetic field (up-and-down or left-to-right) causes a change in resistance, and the different levels of resistance register as 1s or 0s.

Under the current plan, IBM and TDK, an integral player in magnetic recording components for hard drives, will develop a 65-nanometer prototype within the next four years.

IBM has received a new patent, titled - "New Magnetic tunnel junctions for MRAM devices".

Methods of manufacturing MTJ memory cells and structures thereof. A diffusion barrier is disposed between an anti-ferromagnetic layer and a pinned layer of an MTJ memory cell to improve thermal stability of the MTJ memory cell. The diffusion barrier may comprise an amorphous material or a NiFe alloy. An amorphous material may be disposed adjacent a bottom surface of a tunnel junction, within a free layer, or both. An MTJ memory cell with improved thermal stability and decreased Neel coupling is achieved.

The Magnetic Race-Track Memory, a new concept in magnetic non-volatile memory disclosed by IBM Corp of the US in February 2005, is attracting a great deal of attention. If it can be commercialized as advertised it has the potential to revolutionize the memory architecture for computers and consumer electronics. The high potential performance of the new memory is the key, delivering performance on a par with dynamic random-access memory (DRAM) at the manufacturing cost of hard disk drives (HDD). It supports random access, and offers an infinite number of rewrites. Because no mechanism is required, it can be expected to deliver the same robustness as semiconductor memory.

But practical application is still "five to ten years away," said Stuart SP Parkin, IBM fellow SpinApps and director of IBM Research Division, Almaden Research Center at IBM.

The mean access time is about 50ns, which is a little longer than MRAM and roughly the same as existing DRAM.